In defect inspection of a tire surface, a method of inspecting a defect based on a slit light image obtained by irradiation with slit light is used.
An inspection method described in Patent Literature 1 is for performing quality judgment of appearance and shape of a tire based on appearance data by a line sensor of a linear portion irradiated with first slit light on a tire surface and shape data by an area sensor of the same linear portion lighted by second slit light.
Moreover, an inspection method described in Patent Literature 2 is for performing quality judgment of appearance and shape based on density (or color) and position information obtained by shooting an irradiated portion of slit light by an area sensor while rotating a tire.